1. Field of the Invention
The present invention relates to a driver monitoring system, and more particularly to a driver monitoring system for monitoring a driver which drives a motor vehicle in a dangerous state such as looking aside or falling into doze.
2. Field of the Invention
There have been proposed some techniques of for detecting the abnormal driving state of looking aside or falling into a doze by sensing the physiological phenomenon of a driver. These methods includes to use a living body signal and a physical reaction. The former technique observes a living body signal such as a brain wave, skin electric potential and heart beat taken out directly from the driver so that such a phenomenon may be sensed with high accuracy. This technique, however, requires to mount a sensor which is very troublesome by driver. On the other hand, the latter technique has only to observe a change in the movement of the head of a driver so that it does not require for the driver to mount the sensor. This technique, however, is problematic in improvement of accuracy because of indirect judgement of the behavior. The other technique proposed hitherto is to observe a change in the frequency of closing eyes of the driver.
However, the techniques proposed hitherto have the following disadvantages. Where the driver monitoring system is to be mounted on a motor vehicle, the system must satisfy various conditions (1) that the system is portable, (2) that the performance, reliability and safety are assured, and (3) that it does not hinder the driving of a driver.
Therefore, the system must observe the physical reaction of a driver without mounting the sensor and detect it by image processing. Further, the system must acquire the three-dimensional information of a driver's face without mounting the sensor on the driver to detect the inclination of the face of the driver so that the dangerous state of the driver such as such as looking aside or falling into doze is detected.